TY - JOUR T1 - Prolonged Increase in the Sensitivity of the Posterior Ventral Tegmental Area to the Reinforcing Effects of Ethanol following Repeated Exposure to Cycles of Ethanol Access and Deprivation JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 648 LP - 657 DO - 10.1124/jpet.105.084350 VL - 315 IS - 2 AU - Rodd, Zachary A. AU - Bell, Richard L. AU - McQueen, Victoria K. AU - Davids, Michelle R. AU - Hsu, Cathleen C. AU - Murphy, James M. AU - Li, Ting-Kai AU - Lumeng, Lawrence AU - McBride, William J. Y1 - 2005/11/01 UR - http://jpet.aspetjournals.org/content/315/2/648.abstract N2 - The posterior ventral tegmental area (VTA) is a neuroanatomical substrate mediating the reinforcing effects of ethanol in rats. Repeated alcohol deprivations produce robust ethanol intakes of alcohol-preferring (P) rats during relapse and increase the reinforcing effects of oral alcohol self-administration. The objective of this study was to test the hypothesis that alcohol drinking and repeated alcohol deprivations will increase the reinforcing effects of ethanol within the posterior VTA of P rats. Groups of female P rats were used (alcohol-naive, continuous access, and repeatedly deprived). Each rat was implanted with a guide cannula aimed at the posterior VTA. Depression of the active lever produced the infusion of 100 nl of artificial cerebrospinal fluid (CSF) or ethanol (25-300 mg%). Each rat was given only one ethanol concentration during the 4-h sessions conducted every other day. Compared with the infusions of artificial CSF, the alcohol-naive group reliably self-infused 75 and 150 mg% ethanol, but not the lower or higher concentrations. On the other hand, the continuous access group had significantly higher self-infusions of 50, 75, 150, and 300 mg% ethanol compared with artificial CSF infusions. The repeatedly deprived group also self-infused significantly more of 50, 75, 150, and 300 mg% ethanol than artificial CSF; moreover, the number of infusions for all four concentrations was higher in the repeatedly deprived versus the continuous access group. Chronic alcohol drinking by P rats increased the reinforcing effects of ethanol within the posterior VTA, and repeated alcohol deprivations produced a further increase in these reinforcing effects of ethanol. The American Society for Pharmacology and Experimental Therapeutics ER -